Hydraulically driven transit mixer



March 5, 1963 J. w. LENDVED HYDRAUMCALLY DRIVEN TRANSIT MIXER 4Sheets-Sheet 1 Filed April 1, 1959 l A l.

INVEN TOR. JOHN W. LENDVED March 5, 1963 J. w. LENDVED 3,080,152

HYDRAULICALLY DRIVEN TRANSIT MIXER Filed April l, 1959 4 Sheets-Sheet 2FIG.2. 6.24

24 l AJ- it.

' mVENToR.

JOHN W. LENDVED Matth 5, 1963 J. w. I ENDVED HYDRAULIC/my DRIVEN TRANSITMIXER 4 Sheets-Sheet 5 Filed April l, 1959 OQ Hayley Mmh 5, 1963 J. w.ENDS/ED 3,080,152

HYDRAULICALLY DRIVEN TRANSIT MIXER 4 Sheets-Sheet 4 Filed April l, 1959INVEN TOR. JOHN W. LENDVED United States Patent O cousin Filed Apr. l,1959, Ser. No. 8il3,387 1l Claims. (Cl. 259-171) This invention relatesgenerally to transit concrete mixers and more particularly to atruck-mounted mixer having an improved power transmitting and controlapparatus for driving the mixing drum.

Concrete mixers are conventionally mounted on the rear portion of amotor truck for transporting batches of concrete from a central source.The concrete mixers are rotatably mounted for mixing or agitating theconcrete during the travel to the consumer.

Truck-mounted concrete mixers are so arranged that the mixing drum iseither driven by a separate engine carried on the truck or by theinternal-combustion engine of the truck.

The driving power for truck engine driven mixing drums may be takenindirectly from the truck engine through the main clutch and the usualpower transmission mechanism or directly from the crankshaft of theengine. in the indirect power take-off, the speed of rotation of themixing drum is directly rela-ted to the speed of the truck. Furthermore,when the main clutch is disengaged to shift the truck gears, the mixingdrum stops rotating and must be restarted upon re-engaging the clutch.This makes gear shifting ditlicult. Furthermore, the mixing drum oftenturns backwards when the clutch is disengaged because of the unbalanceload in the drum and interferes with rapid clutching and shifting of thetruck. With such previously used mixer driving arrangement, the truckoperator is not therefore free to utilize the truck motor to bestadvantage, particularly when diiicult driving conditions demandflexibility of operation and full power.

Some of the difficulties involved in the indirect power take-off fromthe truck engine to drive the mixing drum have been obviated byarranging a power take-olf connection directly to the engine withoutgoing through the main clutch.

Such connections are usually made at the front end of the truck enginewhere the crankshaft can be most readily connected to a separatetransmission train. However, the transmission trains are relativelycomplicated and troublesome to install on the truck. Furthermore, truckmixers are mounted on commercial trucks of various kinds, and eventhough the trucks are quite similar in appearance and basicconstruction, differences in details of construction necessitate specialmounting arrangements in adapting the mixer drum drive mechanism to eachindividual truck. This makes it diicult and usually impractical totransfer a mixer from trucks of one manufacturer to another.

A separate engine mounted on the truck for driving the mixer istherefore widely used.

The United States Patent 2,696,371 to I. W. Lendved discloses animproved and highly satisfactory separately mounted engine drive. Asmore fully disclosed therein, practically all governmental unitsestablish weight limits than can be carried on the truck wheels oftrucks employing the highways. Normally, the rear wheels are loaded tocapacity prior to the front wheels. If a portion of the load can beshifted to the front wheels, an increased total load can be carried. TheLendved patent provides a separate engine mounted adjacent the rearportion of the truck to shift maximum weight onto the front wheels.

Separate engines requires suitable gear reduction and coupling to themixing drum and normally substantially BQSZ Patented Mar. 5, 1963increase the basic weight of the truck and mixer and reduce the pay loadwhich can be carried in the mixer.

A mechanical drive coupling the drum to the truck engine or to aseparate internal-combustion engine are practically exclusively employedin present commercial truckrnounted mixer. However, hydraulic drives fortruckrnounted mixer are also available.

The known hydraulic drives generally employ a high speed hydraulic motorwhich is coupled to the mixing drum by a suitable gear or chainreduction system. The drives are relatively complicated and heavy.Consequently, such drives reduce the payload which can be carried andare relatively expensive in first cost and maintenance. Further, whenthe direction of rotation of the drum is to be quickly reversed theinertia in the drum establishes relatively large shock forces on thecoupling system.

lt is therefore a general object of the present invention to provide animproved truck-mounted concrete mixer having an improved powertransmitting system for driving the mixing drum of the concrete mixer.

Another object of the invention is to provide an irnproved mixing drumdriving apparatus that may be installed readily on any of varioussupporting vehicles and which establishes excellent distribution of thepayload between the several wheels.

Another object is to provide an easily controlled and smoothly operatinglightweight power transmission mechanism for driving the mixing drum ofa truck mixer from the truck engine.

Another object of the invention is to provide an improved hydraulicallyactuated power transmission mechanism for driving the mixing drum of atruck mounted concrete mixer from the engine of the truck.

Another object is to provide a combined driving motor and main bearingpedestal unit for the mixing drum of a truck mixer.

Another object is to provide an improved truck mounted mixer drivingarrangement including a reversible, variable speed motor directlyconnected to the mixing drum.

Another object is to provide a directly connected driving motor for aconcrete mixing drum so arranged that mixing water may be introducedinto the drum through the shaft of the motor.

According to the invention, a truck mounted concrete mixer is providedwith an improved power transmitting apparatus whereby the mixing drummay be readily driven from the truck engine or other power sourcepreferably in either direction of rotation and at any desired speedwithin a preselected operating range. The improved apparatus of thepresent invention is hydraulically operated, is lightweight, directlyand smoothly controlled through a suitable hydraulic flow control systemand may be installed readily on trucks of various kinds.

The hydraulic transmission system in accordance with a preferredconstruction includes an eiiicient slow-speed reversible hydraulic motorthat is mounted at the front of the drum and is directly connected tothe drum head. Hydraulic iluid under high pressure is supplied to themotor through suitable flexible conduits from a variabledisplacement,reversible-flow pump that is driven preferably by the truck engine. Thehydraulic motor is of the multiple-cylinder, radial type and its powershaft is connected to the drum head to constitute the mixer shaft. Themotor bearings form the main bearing for the drum with the motor housingserving as the front bearing edestal. Since the fluid is pumped at highpressure, the lrequired power may be transmitted at low velocity therebyminimizing power losses and improving operating conditions. A simplecontrol device mounted in the truck cab or elsewhere on the machine maybe operated to adjust the pump for effecting rotation of the mixing drumin either direction at a selected speed.

In accordance with another aspect of the present invenltion, the motoris supported on the truck at a single point by means of a universalpivot support or 4ball joint to correspondingly support the adjacent endof the drum. The opposite endof the drum is supportedin the usual mannerona pair of spaced rollers.` The rollers and the ballitype jointyestablishes a three-'point mounting systeml for the mixing drum whichavoids stresses which might otherwiseeresult. from bending and twistingof the truck frame in operating lover roughpterrain.

The ball-type joint endofthe drum is stabilized on its single. supportpoint by atorqueresisting.;` or stabilizing strutfthatisinter-connectedbetween the motorl and the truclgframefto prevent lateralswinging movement of the drum.

the motor is directly connected tothedrum end,` itreijuir'esllittlespace thereby enablingthe drum to `be positionedforwardlyon the truckfor best weight distribution.l l

Thehydraulic fluid circulates` inaclosed. circuit between'thepump andthe motor, the circuit being so arranged that 'the motoroperates also asa brake to keep the'drum 4always under control whereby the drum maybestar-ted smoothly, reversed orstopped with minimum slio'clcl Since thepower connection between the truck engine and the drum driving-motor maybe effected through iiexible conduitsy the ,apparatus may be mounted inthe most favorable positions onany suitable mo-tor .truck orVtransferred from one truck -to another and the conduits installed; withminimum modification of the structure.

' The foregoing and other objects of this invention will.

become more fully apparent from the following detailed 4description of apreferred embodiment of an improved truck mounted concrete mixerconstructed .in accordance with'the present invention. 4

'I'he drawings furnished herewith illustrate the best lInode presentlycontemplated for carrying out the invention. i

In the drawings:

FIG.l l'is a side elevational view with parts broken away ofa'truck-mounted concrete mixer incorporating la pre,- ferred embodimentof the mixer drive in accordance with the" present invention;

yFIG. 2 is the fragmentary view taken upon a line 2,-2 ofFIG. l; i

FIG. 3 is -a view partlyin section and partly in elevation generallytaken on line 3--3 of FIG. 2;

FIG. 4`is a front elevational'view of the hydraulic motor-shown in FIGS.2 and 3 with the principal plane of the motor pivoted to a Verticalplane;

FIG. 5 is a cross section of a iluid distributing valve shown in FIGS.1-3; and

FIG( 6` is a simplified diagrammatic circuit lof the hydraulic powersystem adapted to the drive shown in FIGS. 1'-5.

Referring to the Adrawings and particularly to FIG. l, a truck mountedconcretev mixed constructed in accordancewith the present invention isshown generally including a mixing drum 1 which is rotatably mounted onthe rear portion of a truck frame 2 of a conventional type truckl toform a truck mounted transit mixer adapted lfordeliveryand mixing ofconcrete, not shown.

The truck includes a pair of forw-ard front steering wheels 4 -andtandemrear wheels Swhich are connected to the frame `2 in any suitable mannerto allow movement ofthe truck'. The frame 2 conventionally consists of apair of .laterally spaced longitudinally extending channel memberswhich. are interconnected to form a rigid andrm understructure forsupporting the various operating members of the Vtruck andthe mixingdrum. An int'rfnalcombustion yengine 6 is secured t-o the forwardportionfof the'frame 2 and coupled to the rear wheels 5 througha,conventional gear transmission unit 7 to supply` power'to the rearwheels S and movethe truck 3.

A cab 8 is secured to the forward portion of the frame 2 enclosing theengine 6 and the various steering and riding components of the truck 3and provides -a protec- `tive enclosure for the truck operator, notshown.

The truck 3 is generally representative of vehicles which are presentlymade to carry a mixing drum 1 and the load or batchof concrete, notshown. The particular truck 3 is generally typical of variouscommercially availfable motor ,trucks although the various constructiondetails may varyconsiderably. Generally, however, the back frameportions are formed substantially identical to each other to accommodatethe various containers and structures which. are conventionallymanufactured and secured to the-trucks by others..

Themixing drumlis generally anelongaltedtapered cyinder having an outer,tear drop.I configuration.

A plurality .otgcirctmifcrent-ially distributed spiral :vanes Qlarewelded withinthe rnixingdrum 1 todischarge or, to the.concrete, notshown, inaccordance 'witlrthe4 directionofrotation of thedrurrrll,v assubsequentlyy de: scribed. The back end of the drum l is formed with anopening. l@ through which concrete is selectively admitted anddischarged. A hopper 1i is mounted in communication, with-the openingitl 'toV directconorete intov lland `the conorete, not shown.: Hatclrlmay alsobe.

employed for. charging `drum .1.

The .mixing drum l is rotatably vsupjmrted upon .the back portion of theframe 2 by a forward .drive .and bear, ing unit M anda rear bearing uniti5. lr6 are spaced in accordance with the members. offrarne 2- andwelded orotherwise secured .tothe bearing units 14 and .15. The bearingunits .I4 and lSiare. secured to.

frame 2 .with .theZ-bars ldrestingon the adjacent frame members to.support drum 1 extending. longitudinally of .the truck .3 .with .theheadA of rear of cabs.

The rearfbearing unit V15 supports theback .end of the mixing drum labove the head of the drum to bias the concrete, not shown, to the.forward portion :of the mixing drum l. and thus maintain the maximumpossibleweight toward the yforward o-r frontpart. of the truck 3 andthus on the front steering wheels 4.

The mixing drum il is thus adapted to be mounted on any one'of thevarious commercially available trucks and to be remounted upon a newtruckA incident to damage or obsolescence of truck 3.

Z-bars Mare `secured to the truck frame 2 by a plurality of standardbolt and nut clamp `assemblies 117 to tiethe `back bearing unit 15 Ytothe truck frame 2.

Theillustrated bearing unit 15 is generally similar tto thatshown in thepreviously referred to U.S. Patent No. 2,696,371 and comprises a'box-like cro-ss brace 18V forming a bearing pedestal which extendsupwardly and'A slightly. forwardly from the rear end of the Z-bars 16and the frame 2. adjacent the rear par-t of the mixing drum 1. A pair`of laterally spaced rollers i9 'are rotatably mounted on the upper endof the cross brace i8 to rotatably support the rear or bacicv end of themixing drum il. A ring -trackway Ztl is secured or otherwise formed onthe outer circumference of the mixing drum 1 in alignment with therollers Il. Afshield and bracket support 2l encircles the trackway Ztlas an extension from the cross brace 18.

A pair of rearwardlyprojected brackets 22, of which only one is shown,are Secured` to opposite sides of the the truckframe 2 to supporttheffronft endof the drum 1" Ay pair `of Z-bars the .drum l .adjacent the f4in the illustrated embodiment of the invention as follows.

Referring particularly to FiGS. l-3, a box-like arcuate bridge member 23constituting a lateral mounting brace is secured between a pair oflaterally spaced end or junction plates 24 which extend downwardlyimmediately adjacent the outer walls of the frame 2. The plates -24flare forwardly and rearwardly of the bridge member 23 and are securedto the frame 2 by a plurality of bolts 25 to transmit the drum load tothe frame 2v. A triangular foot member 26 constituting a loaddistributing brace is welded to the undersurface o-f the bridge meinber23 and the adjacent plate 24 and res-ts on the upper Wall of thecorresponding portion of frame 2 to distribute the load. The plates 24are welded to the forward end of the Z-bars i6 to tie 4the forwardbearing ld tothe rear bearing unit 15. A portion of the top wall of theZ-bars 16 is removed as `at 27 to accommodate the rearwardly =flaredportion of plate 24.

A supporting socket member 2S of a two-piece balltype socket 29inclu-des a depending bracket 3) which is welded to the top and the rearwalls of the bridge ymember 23 midway between the plates 24. An upperretaining socket member 31 is releasably bolted to the bearing socketmember 28 by a pair of oppositely disposed bolts 32, which extendthrough suitable openings in the member 28 and thread intocorrespondingly tappe-d openings in the retaining member 3l. The bearingmember 23 is provided with a hemispherical recess opening vertically andrearwardly upwardly toward the mixing drum l. A

bearing ball 33 is disposed within the hemispherical ren cess andpivotally clamped therein by the retaining socket member 31 which has acorrespondingly shaped recess.

The bearing ball 33 includes an integral shank 34 which extendsvertically upwardly therefrom with the axis of the shank `and bearingball lying in a plane which is perpendicularly related to the axis ofthe mixing drum 1. The shank 34% is secured within a correspondingopening in the forward drive and bearing unit ift- An encircling ange 3Sis welded to the shank 34 adjacent the bearing ball 33 and is bolted asby bolts 3e to the forward drive and bearing unit which is therebypivotally secured to the truck frame 2.

The bearing ball 33 in combination with the rollers 19 establish athree-point suspension for the mixing drum l and prevent the twisting ofthe truck frame 2 from being transferred to the forward bearing unit U.Consequen-tly, high stresses inthe frame of the front bearing unit 14are prevented.

In the illustrated embodiment of the present invention, the forwardbearing unit llil is a multi-cylinder, radial hydraulic motor whichconstitutes the forward rotating support for the mixing drum 1 and thepower source to lrotate the mixing drum 1.

The bearing unit i4 generally includes a ring-shaped motor housing 374to which the bearing ball 33 is rigidly secured by flange 35 and boi-ts36. A front closure and bearing plate 3S is removably secured to thering-shaped housing 37 by bolts 3x9 to removably close the forwardopening of the housing. An integral rear closure and bearing plate 4bcloses the drum side of the ring-shaped housing 37.

A drive or crankshaft 41 is rotatably secured within the housing 37 by afront bearing 42 centrally located in the front closure and bearingplate 3S and a bearing 43 which is centraily located in the integrallyformed rear closure and bearing plate 4d. The front bearing 42 is aconventional double roll radial bearing and the rear bearing 43 is aconventional tapered roller self-aligning roller bearing. As thebearings are conventional, no further description thereof is given.

The drive shaft 4l extends rearwardly through the bearing plate 4t) inalignment with the axis of drum l. The shaft 4l is rigidly coupled tothe front end of the d mixing drum 1 to form the forward trunnion of themixing drum l as follows.

Referring particularly to FIG. 3, a coupling hub 44 is secured to theforward wall 45 of the mixing drum 1. An annular plate member 46 iswelded to the inner surface of the wall 45 and to the innerportion ofthe hub #i4 to rigidly support the hub on the mixing drum ll. Thecoupling hub 44 and the rearwardly extending portion of the shaft el arecorrespondingly splined as at d'7 to interlock the shaft 41 and drum iand cause simultaneous rotation. Suitable lock nuts 48 thread onto theinnermost end of the shaft 4l, which is correspondingly threaded, tolock the hub i4 on the extended end of the drive shaft 4l. Consequently,rotation of the drive shaft 4i. is transmitted to the mixing drum 1 torotate the concrete, not shown, which is supported within the drum.

The crankshaft 4l is provided with a central axial passage 49 whichextends the complete length of the crankshaft and which is adapted to beconnected to a water tank, not shown, which may be supported in anysuitable manner on the truck, the forward bearing unit 14 or the like.In the illustrated embodiment of the invention, the opposite ends of thecentral Water passage 419 are closed by suitable cap assemblies 5t? and5l which are releasably secured to the crankshaft 4l. rthe United StatesPatent 2,534,445 which issued to T. K. Hilkemeier on December 19, i950,discloses a particularly satisfactory construction for a waterconnection which may be readily applied to the illustrated crankshaft41.

The ball-type socket 29 is secured to the motor housing 37 by the ballshank .34 somewhat forwardly of the principal plane through the housing3'7 to substantially vertically align the rear bearing 43 with the ball.33. rl`he load forces transmitted to the frame 2 through the ballsocket 29, particularly while braking the truck 3, include a horizontalcomponent and a vertical component which combine into a resultant forceextending angularly forwardiy and downwardly. The movement of the ballsocket 29 forwardly, as shown, brings the line between the bearing 43and the ball 33 more nearly in alignment with the resultant force andimproves the transfer of the horizontal and vertical forces to the frame2.

Referring particularly to FlGS. 3 and 4, a disc crank 52 is integrallyformed on the crankshaft il and extends radially within the housing 37.The disc crank 52 is a circular member eccentrically arranged withrespect to the axis of the shaft 4i such that rotation of the crankshaft4l and the integeral disc crank 52 causes the true centerof the disccrank to define a circle about the axis of rotation. The outer peripheryof the disc crank 52 is axially hanged as at 53 to establish arelatively wide ringlike surface spaced from the outer wall of thehousing .37. The disc crank 52 is adapted to be rotated by a pluralityof uid actuated pistons 54 which are slidably journaled within cylindersS5 radially aligned with the crank 52.

The illustrated fluid motor includes five cooperating pistons 54 andcylinders 55 which are successively powered to cause smooth and positiverotation of the crank 41. Although any number of cylinders can beemployed, more than three cylinders are necessary to make the motorself-starting. An odd number of cylinders results in minimum variationin pressure for each revolution of the drum. Each piston and cylinderarrangement is identical in the illustrated embodiment of the inventionand consequently only one is described in detail.

Each cylinder 5S is an elongated cup-shaped member which is securedwithin a tubular hub 56 formed in the motor housing 37 in alignment withthe plane extending through the disc crank 52. The cylinder 55 includesan integral upper head 57 substantially closing the outer end of thecylinder. A stop ring 58 is secured within a suitable encircling recesson the inner portion of the cylinder 5S. The ring 58 extends radiallyfrom the cylinder 55 and mates with a corresponding recess formed on theinner-edge of thetubular hub 56 to prevent or limit the outward movementof the cup-shaped cylinder. A C- shaped clamp 59 encircles the cylinder55 immediately adjacent the outer'end of hub 56 and rests or engages theouter end surface of the hub. The adjacent upper edge of clamp 59 andanadjacent enlargement of the cyiinder 55 are provided withcorrespondingly chamfered edges 69 such that tightening of the clampprevents or limits inwardly movement of the cylinder S and rigidlyclamps the cylinder within the hubi56.

A suitable opening 6l is provided in the head S7 of each cylinder 55. toreceive a uid line 6.2- through which a .fluid 63, shown. in FIG. 4, issequentially selectively admitted andy discharged. from the cylinder 55to reciprocate the, pistons S4, and drive the disc crank 52v andattached crankshaft 41 as more fully described hereinafter.

The piston 54 is generallya cup-shapedmember which isslidablyv supportedwithin the cylinders 55. Oil rings 64. substantially seal the slidingsurfaces .between the piston S4. andi the inner wall of the cylinders55; A piston o1' connecting `rod` 65 ispivotally secured tothe piston54' and slidably coupled to the disc crank flange 53.

The piston end of connecting rod 65 and the adjacent surface Aof thepiston. 54 are correspondingly spherically recessed totreceive a pivotball 66. A ring retainer `67l isv secured Within the piston 54 and in.engagement with an enlargement 68 on the inner end ofthe piston rod bya-:suitable coil spring 69 and a split ring 70 torpivotally andresiliently couple the rod 65 to the piston 54.

"Ehe opposite end ofthepiston rod @Sis provided withanintegraltriangular shoe 7i having a bearing portion- 721wiuchycorrespondsgenerally to the width of the crank flange 53 and extendscircurnferentiallyl of the crank 52.- A radial projection '73 is formedon the outer periphery lofone side ofthe connect-ing rodshoe 72 `and asplit clamp ring 74 having-aninwardly opening recess is dis-- posed;over the` projection toradial-ly couple the connecting rods yd5inbearing engagement with thecrank 52,

Referring particularly to FIG. 4, the hydraulic motor is sho-wn with-thetop anduj'sperl right cylindersconnected tol a source of high pressureas subsequently described to receivevuid and tornove the pistons S4 andIattached bearing shoes 72 inwardly. The line of force on-crank 52 isoff center with respect to-shait and thus the crank 52 rotates in 'acounterclockwise direction. The upper left cylinder 55 is ondead'centerY with its line of force' aligned with the center-of shaftdit and the true center of crank 52. The lower left and right cylinders'yare connected to the low pressure :side of the source, as subsequentlydescribed, to discharge the actuating iuid 63 and allow inw-ard movementof the corresponding Ipistons' 54. The cylinders' receiving anddischarging iiuid are outof phase or step with each other to provideoverlapping of the power cycles. The cylinders S5 are sequentiallypowerediwith the slight overlap in the `power cycle of adjacentcylinders to establish a smooth and continuous rotation ofthe crank 52.

To reverse the direction of rotation, with the motor in the stateillustrated in FIG; 4, the two lower cylinders 55 are connected'to thehigh pressure side of a source land the-toptandY upper right cylindersare connected to the low pressure side of the source. Thus, thedirection of rotation is controlled by the sequential direction in whichfluid is applied to the successive cylinders 55. Consequently,successive actuation of the pistons Sd by .the incoming fluid 63 whichis admitted via :duid lines 62 `and the, fluid openings 6l continuouslyshifts the position ofthe several shoes 72 and causes rotation of thecrank 52i and the attached shaft 41.

The connecting -rods 65 oscillate slightly about the ball pivot 6 6 inaccord-ance with the superimposed straight line motionaifected by thesuccessive. cylinders to allow the simultaneousmovement of theshoes-'72m two rela.- tive directions.

A portion of the Iincoming iluid 63 to the cylinder 55 is. used toestablish forced lubrication between the shoes 72 and the crank ange 53and to thereby reduce the friction forces and allow smooth rotation ofthe crank 52. Radially aligned oil passages 75, 76, and 77 arerespectively formed in the piston 54, the pivot ball 6dl andtheconnecting rod 65 to 'allow a relatively minute quantity of incomingfluid `63 to flow radially into the interface area between the bearingportion. 72 of shoe 71 and the crank flange 53. The. lubricating oilkflows 'between the bearing portion 72y of shoe 71 and the crank flange53 of crank 52A and discharges: into they housing 57;

An oil drain 7S is4 secured to the lower end of the housing 37 to drainolf the accumulated lubricating duid and to return itv into the system,as subsequentlydescribed'.

The hydraulic motor thus serves to` rotate the mix-ing drum l as well asto simultaneously constitute the for werd bearing support for the mixingdrum.

Referring particularly toV FIGS. 2 and' 3', at pair of superposed rigidtorque resisting rods 79" and' girare pivotally secured at one end tothe housing 37 andi at' the opposite end. to one of the ybearingplates24 by suitable knuckle joints 81. Each of the knuckle joints. Si."includes a pair of inwardly extendingpins S2 secured to, the end of rods79 and dit and toa bearing ball 83.'. The bearing balls 83 are mountedfor universal pivotal' movement w-ithin` corresponding sphericallysurfaced openings formed in Ia pair of mating lugs Sd which' areVrespectively welded tothe housing 37 rand mounting plate 24. The torquerods 79 and S0 prevent `lateralswinging of the drum and stabilize themounting of the drum` 1L on pivot support 29.

Referring particularly to FIGURES l, 3` and 6,: the actuating fluid 63supplied to the hydraulic motor cylinders S5 is preferably alow-velocity, high pressure fluid from asuitable fluid pump Svdri-ven bythetru-ckl engine 6. High working pressures create less heat loss,eliminating the need for a heat exchanger, and aregenerally moreefcient. Further, the distributing system is simpler and the hydraulicmotor can within practical limits be reduced in size. As a practicaleconomic construction, 4000 pounds per square inchv presently ap-` pearsto provide thebest design.

The pump S5' is mounted on the truck frame 2V adjacent the engine 6. Abelt connection st connectsthe fluid pump 8:3 to a forward enginecrankshaft extension for operation incident to running of the truckengine 6. The liuid pump 85 is preferably a variable-displacement re'-verse-iiow type pump of :the swash plate design which is commerci-allyavailable and is adapted to establish a low velocity, high pressurefluid ow. The pump 85 is -zherefore shown by a conventional lgraphicalsymbol in A fluid distributing valve 87, mounted on the hydraulic motorhousing 37, is connected to the output of the liuidpump 85 by a pair oftnansporting flexible conduits 88 and 89. The conduits 88 and 89selectively connected to thevhigh andl lou/pressure sides of the pump 55for. forward and reverse rotati-onof the' mixing dri'i l.

Referring particularly to FIGS. 3 and 5, the valve-8'!l includes ahousing 90 which is secured within an opening in the motor-housing 37.A' pair offspaeed inlet-outlet ports 91 and 92 are provided in theexterior wall of the housing 90 and are coupled to the uid pipes 8S and@and a plurality of distributing ports 93 are provided and connected tothe several fluid lines 62 for carrying the fluid to cylinders 555. Arotatable valve drum 94- is journaled within the distributing valvehousing 90 between the ports 91 and 92' and the ports 93. The. drum 94includes suitable distributing passages 95which are adapted tosuccessively connect the inlet-'outlet ports 9l'and'92'to theindividu-al distributing ports`93 and' thus to thecylinders `55'. Adrive Mjand extends outwardly through housingSd andinto the arealternatelyy shaft 9G is'secured to' the 'valvedrum motor housing 37. Agear 97 is secured to the extended end of the shaft 96 and is connectedby a suitable idler gear 98 to a drive gear @9 which is secured aboutthe hydraulic motor shaft lll. The gear 9d is rotatably mounted on theadjacent portion of the hydraulic motor and establishes timedsynchronous rotation of the valve drum 94 with shaft 4l. Consequently,as the motor shaft 4l rotates the valve drum 9d is slowly rotated tosuccessively connect the inlet-outlet ports 91 and 92 to thedistributing ports 93 to simultaneously supply high-pressure fluid 63 tocertain of the cylinders 55 and to withdraw fluid from other cylinders.

The direction of rotation of the motor is determined by which of theinlet-outlet ports 91 and 92 is connected :to the high pressure side ofthe pump 85. lf port 91 is connected to the high pressure side of pump3d, the seuence of lluid application is in one direction, assumedarbitrarily to be in a counterclockwise direction as viewed in FIGURE 4.Then, it port 92 is connected to the high pressure side of the pump S5,the sequence of luid application to the cylinders 5S is in a reverse orclockwise direction. Consequently, the direction of rotation of drum lis easily and readily controlled in accordance with the operation ofpump Se'.

The illustrated rotary valve is relatively simple and eliminates theshocks created by the conventional spool valve, the results of which areditlicult and expensive to control,

The `hydraulic circuit may be formed in any conventional or desiredmanner. A simplified diagrammatic hydraulic how circuit is shown inFlGURE `6 for purposes of fully and clearly explaining the functioningof the present invention.

Referring particularly to FIGURE 6, the illustrated circuit is aclosed-loop hydraulic system extending between the hydraulic motor andbearing unit lll and the pump 35. The truck engine 6 is connected todrive the fluid pump S5 which in turn is connected to the distributorvalve S7 by the conduits 553 and 89.

A control lever lli@ is connected to the pump 8S by a suitablemechanical linkage or the like, as shown in PIG. l, and controls thedirection of uid ilow through the pump and consequently determines thehigh and low pressure connection of the pump 5S to conduits S8 and 89.The control lever ldd has a forward position, shown in phantom to theright in the FIG. 6, and it is assumed for purposes of illustration thatin this position, luid flow is through the pump S5 from conduit S9 toconduit SS and consequently conduit SS is connected to the high pressureside of tie ump 5S and conduit 89 is connected to the low pressure sideor" the pump. The control lever ldd has a reverse position, shown inphantom to the left in FIG. 6, in which position a reverse luid low isestablished by pump $5 and the conduit 83 is now connected to the lowpressure side of the pump and the conduit S9 is connected to the highpressure side.

The control lever litt when centrally located between the forwardposition and the reverse position, as shown, constitutes a neutralposition wherein the conduits 8d and 39 are effectively disconnectedfrom the pump SS and lock the fluid within the motor circuit.

The intermediate positions of the control lever jlttl between theneutral position and the full forward or reverse posi-tion throttles thefluid pressure and thereby regulates the speed of rotation of the mixingdrum l. This provides a reliable stepless control giving an innitenumber of speeds within a predetermined range.

Further, when the hydraulic motor is operating in one direction and isto be quickly reversed, the mixing drum 1 is braked and establishment ofhigh shock forces is eliminated. As the operator moves the control leverlll@ toward the neutral position, the uid flow to the cylinders 55 isprogressively reduced and `the motor speed reduced accordingly. When theneutral position is reached, the fluid 63 is locked in the circuit andbrakes the drum l to 19,- prevent large shock forces incident to thereverse positioning of the lever Mit).

The control of the direction and speed of rota-tion of the mixing drumis therefore simple and cannot be operated in a manner to cause damageto an expensive coupling system as in conventional mixing units.Consequently, unskilled personnel can be employed to operate the mixingdrum.

The control lever ftd@ constituting a manual control is mounted withinthe cab of the truck 3 and connected to pump by a suitable couplingcable, not shown, to allow ready and convenient location of the controladjacent the operator, not shown.

A small oil reservoir lill is mounted on the truck 3 and connected tothe crankcase drain 78 to collect the lubricating oil by-passed throughthe hydraulic motor, as previously described. Because the hydraulicpower system to the motor and bearing unit 14 is a closed loop, thereservoir 161 is small and does not add appreciably to the weight ofthetruck and mixing components.

A make-up pump M2, shown in FIG. 6, connects the oil reservoir lill tothe lluid conduits 3S and 89 to make up or return the withdrawn huidinto the system and thereby to maintain a constant volume in the closedloop between the motor and the pump S5. Check valves 193 and ldd areconnected in parallel 'between each of the conduits 88 and 39 and themake-up pump ltlZ to prevent a reverse llow of fluid from thecorresponding conduits. Consequently, the volume of fluid within theclosed loop driving the hydraulic motor is maintained at a constantvalue.

A suitable pulley connection connects the makeup pump lli?. to theengine 6 for operation of the makeup pump whenever the hydraulic motoris operated. The pump to2 and connecting conduits are only shown in FIG.6 for clarity of illustration.

The present invention provides a motor for directly driving the mixingdrum l from the truck engine 6 without the necessity of complicatedpower transmission apparatus which is both diicult to install andmaintain. The speed of the mixing and discharging can be independentlyestablished with a continuous and line adjustment within a relativelywide range through a simple and economic control unit. The term mixingis broadly employed in the present application to define theconventional mixing of the aggregate to form the concrete and also thenormal agitation of a premixed concrete which is disposed within thedrum for transportation.

Thus, the drum may readily be rotated from 0 up to l5 or i8 revolutionsper minute while maintaining normal engine speed. The vdrum l cantherefore be rapidly rotated to discharge the concrete while the truckis moved forwardly at a relatively lOw speed.

The direct connection of the hydraulic pump to the engine establishesindependent operation of the mixing drum and the propulsion of truck 3.The starting and the stopping of the truck and the changing of the truckdriving gears can be readily and rapidly controlled in the mostadvantageous manner. Further, the truckmounted mixer of the presentinvention can be operated without any substantial training withoutclashing of the gear and destruction of the clutch.

The combined bearing and driving motor of the present invention allows amost advantageous distribution of the weight ot the truck, mixingapparatus and the concrete contained therein upon the truck wheels suchthat the percentage of the total weight applied to the rearward wheelsis maintained at a minimum. Consequently, an increased total load can becarried.

The mixing drum of the present invention is readily mounted on anyconventional truck vehicle and is readily interchanged to a new truckwhenever necessary.

The direct interconnection of the hydraulic motor as a forward bearingunit reduces the number of separate components mounted on the truck andinterconnected ege-sai 1l with the' drum and permits a more moderndesign of a truck mounted mixer.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

-I'claim:

l. A drive mount for a tubular shaped mixing drum havin-g laclosed endfor mounting on' the frame of a truck, whichl comprises a hydraulicmotor includinghousf ing' and a driven shaft rotatably mounted in thehousing, means to connect the driven shaft to 4the elo-sed end of themixing drum to rotate the mixing drum, and a universal pivotl supportsecured to the housing and having attachment means for securement'ltothe frame of the truck toy transmit the concentrated load presented atthe'closed end ofthe drum directly to the frame.

2. A drive mount' for a tubular shaped mixing drum havinga closed endfor mounting on the channel frame of a truck, which comprises ahydraulic motor including a housing and a driven shaft rotatably mountedin the housing, meansto connect the driven shaft to the mixing drum-torotate the mixingV drum, a universalpivot supp-ort secured to thehousing', and attachment means secured to the pivot support andincluding sidel plate members; extending downwardly adjacent the outerVsurfaces of the' frame and having bolt receiving means for bolting ofthe side plate'members to the frame of' the truckto transmit theconcentrated load presented at the' closed'end of the drum directly tothe frame in thev assembled position.

3'. -A truck-mounted` concrete mixer includingv a concrete mixing drumadapted to be rotatably mounted on a frame of a conventional motor truckhaving a running controly transmission and an engine operativelyconnected to drive said contro-l transmission, said mixingv drum beingclosed at its forward end and open at its rear- Ward end, whichjcomprises-a variable displacement reversible-iiow high-pressure pumpoperatively' connected to' be driven by'said truck engine independentlyof said running control transmission, control apparatus arranged toVcontrol said pump'as to volume and' direction of fiuidow therefrom,bearing means disposed to rotatablysupport said open rearward end ofsaid drum, a multiradial-cylinder hydraulic motor having a rotatingshaft secure'd'to the closed forward'end ofthe drum, a ball a'ndsocketjoint disposed to support said hydraulic motor ou said motor truck at asingle point for universal pivoting movement thereon, a torque-resistingstrut interposed between said hydraulic motor and said truck' tostabilize iSaidfmotor and said mixing drum` in operating position whilepermitting relative movement between said mixing drum and said truck toaccommodate deflections of said truck, and flexible fluid conduits'sequentially conn'ectedr4 between said'high pressure pump and thecylinders ofsaid hydraulic motor to drive said mixing drum in eitherdirection at desired speed incident to predetermined actuation of saidlcontrol apparatus.

4; In a transit mixer for transporting and mixing a batch of concrete orthe like including a motor truck having a drive engine on one end of thetruck and a mixing drum rotatably mounted on the opposite end of saidtruck for receiving a batch ofconcrete to be transported, ak highpressure reversible hydraulic motor having a rotating.' member rotatableat the velocity range of the mixing drum, said rotating member beingdirectly connected to the'engineend of said mixing drum to directlyrotate the drum at the' sameV angular velocity as the motor, a highpressure variableV capacity pump operatively connected to'be driven bysaid truck engine and to drive said hydraulic motor, and controlapparatus operatively connected to adjust 'said variablecapacity pump ina manner to regulate' the speed and'direction of rotation of saidmixing" 'drum'. c

5: In' a' transit concrete mixer' of the' type having a rotatable mixingdrum carried by a self-propelled vehicle having a driving engine, aVariable capacity reversing ow pump connected to be driven by saidvehicle driving engine independently of the'l vehicle propulsionconnection of said engine, manually operable control means arranged toadjust said pump to supply pressure fluid at selected rate in selecteddirection of ow from saidl pump, a hydraulic motor directly connected tosaid mixing drum to rotate the drum at the same velocity as thehydraulic motor, fluid conduit means operatively connecting saidvariable capacity reversing ow pumpl to said hydraulic motor wherebysaid rotatable mixing drum may be driven in either direction aspredetermined speed selectively by controlling said pump independently'of the propulsion of said vehicle, andI a universal joint secured to thetruck and thelhydraulic motor and constituting the support for theadjacent end of the drum.

6. In a motor-truck transit mixer having a driving engine on one end ofthe truck and having a concrete mixing drum rotatably mounted on theopposite end of the truclt for containing a batch of' concrete andtransporting the batch of concrete, a slow speedA hydraulic motor havinga motor housing and a power rotated member directly connected to saidmixing drum adjacent said engine, a ball socket joint mounting saidmotor housing on said truck to rotatably support the drum, a variablecapacity hydraulicpump mounted adjacent the engineand operativelyconnected to be driven by said truck driving engine, fluid conduit meansinterconnecting said pump and said'hydraulic motor to selectively drivethe rotatable member of the motor and attached drum incident to saidpump being driven by said engine, and' control means operativelyconnected to adjust the pumping capacity of said pump thereby toregulate the iiuid pressure to said motor to regulate the speed -ofrotation of said mixing drum. l

7. In a transit concrete mixer, including va vehicle having spacedrunning wheels secured to a yieldable frame subject to deiiection whenoperating overuneven terrain; av mixing drum closed at one end and openat the other end to receive a batch of concrete to be mixed andtransported and adapted toV be secured to theframe close to certainrunning wheels and spaced'from other running wheels, a motor providedwith a protruding drive shaft that is rigidly xed to the closed end ofsaid mixing drum in a manner to rotatably support said drum end and torotate the drum, means arranged to support said motor on said vehicleframe for universal relative movement to accommodate deiiection of saidframe, means arranged to support said open end of said drum for rotationon said frame in a` manner to accommodate deiiection of said frame, anda torque arm connected between said frame andsaid universally mountedmotor to maintain said motor in position relative to said framey forsupporting said closed end'of said drum for rotation on said frame, thearrangement being such that said drum may be rotated as said vehiclevtraverses uneven terrain without detrimental effects upon said drum orits driving motor resulting from deflection of said yieldable frame.

8. In a transit concrete mixer including a wheeled conveyance having ayieldable frame, a mixing drum for transporting and mixing concrete,said drum being open at one end and presenting an axially disposed shaftat-the other end, a pair of spaced rollers rotatably mounted on saidyieldable conveyance frame in a position to support the open end of saidmixing drum, and a `drum driving motor comprising a stator and a drivenrotor mounted with said driven rotor rigidly connected to said shaft ofsaid drumy and with said stator mounted for universal movement on saidyieldable conveyance frame and constituting the support for thecorresponding end of the drum, the arrangement being such that saidmixing drum and said motor are rigidly interconnected as a unitarystructure that is'mounted at vthree points on said yieldable framewhereby weaving of said yieldable frame may occur as said conveyancemoves over uneven surfaces.

9. A drive mount for a tubular shaped mixing drum having a closed endfor mounting on the channel frame of a truck, which comprises ahydraulic motor including a relatively stationary housing and a drivenshaft rotatably mounted in the housing, means to connect the drivenshaft to the mixing drum to rotate the mixing drum, a ball pivot supporthaving a ball member and a socket member one of which is secured to thehousing, a lateral mounting `brace secured to the opposite member of thepivot support, and junction plates secured to the brace and adapted toproject downwardly adjacent the outer surfaces of the frame with thebrace resting on the frame and adapted to be lbolted to the frame of thetruck to transmit the concentrated load presented at the closed end ofthe drum directly to the frame.

10. A drive mount for a tubular shaped mixing drum having -a closed endfor mounting on the channel frame of a truck, which comprises ahydraulic motor including a relatively stationary housing and a drivenshaft rotatably mounted in the housing, means to connect the drivenshaft to the mixing drum to rotate the mixing drum, a ball pivot supporthaving ta ball member and a socket member one of which is secured to thehousing, a lateral mounting brace secured to the opposite member of thepivot support, junction plates secured to the brace and projectingdownwardly adjacent the outer surfaces of the frame in the assembledposition and being bolted to the frame of the truck to transmit theconcentrated load presented at the closed end of the drum directly tothe frame, and load distributing braces secured to the mounting braceimmediately adjacent said junction plates and resting upon the adjacentmembers of the channel frame of the truck.

11. In a concrete mixer having a generally tubular mixing drum mountedon a truck frame and rotated about the axis of the drum, a radialhydraulic motor having a housing with a plurality of circumferentiallydistributed cylinders lying in a common plane and pistons in saidcylinders directly coupled to drive a crank and a shaft centrallyjournalled in forward and rear bearings in said housing, said shaftextending perpendicular to said common plane, means to rigidly couplethe motor shaft to the drum in alignment with the drum axis, universalsupport means secured to said truck frame and to said motor in slightlyspaced forward relation to said common plane to establish asubstantially vertical line extending between the rear bearing for saidshaft and said support means, and bearing means secured to said frame torotatably support the opposite end of the mixing drum with the axis ofthe drum extending downwardly therefrom in alignment with the motorshaft.

References Cited in the le of this patent UNITED STATES PATENTS1,547,409 Cacaud July 28, 1925 2,098,214 Benedek Nov. 9, 1937 2,256,324Orshansky Sept. 16, 1941 2,350,285 Maxon May 30, 1944 2,511,240 Bohmeret al. lune 13, 1950 2,530,241 Harrington Nov. 14, 1950 2,541,228Fitzgibbon Feb. 13, 1951 2,563,336 Jaeger Aug. 7, 1951 2,572,058Sarasody Oct. 23, 1951 2,611,649 Johnson et al Sept. 23, 1952 2,624,557Gerst Jan. 6, 1953 2,639,586 Muller May 26, 1953 2,706,623 Styes Apr.19, 1955 2,732,189 Gerst Jan. 24, 1956 2,787,065 Bock et al. Apr. 2,1957 2,812,638 Timms Nov. 12,1 957 2,901,975 Grad Sept. 1, 1959 FOREIGNPATENTS 464,044 Germany Aug. 7, 1928

3. A TRUCK-MOUNTED CONCRETE MIXER INCLUDING A CONCRETE MIXING DRUMADAPTED TO BE ROTATABLY MOUNTED ON A FRAME OF A CONVENTIONAL MOTOR TRUCKHAVING A RUNNING CONTROL TRANSMISSION AND AN ENGINE OPERATIVELYCONNECTED TO DRIVE SAID CONTROL TRANSMISSION, SAID MIXING DRUM BEINGCLOSED AT ITS FORWARD END AND OPEN AT ITS REARWARD END, WHICH COMPRISESA VARIABLE DISPLACEMENT REVERSIBLE-FLOW HIGH-PRESSURE PUMP OPERATIVELYCONNECTED TO BE DRIVEN BY SAID TRUCK ENGINE INDEPENDENTLY OF SAIDRUNNING CONTROL TRANSMISSION, CONTROL APPARATUS ARRANGED TO CONTROL SAIDPUMP AS TO VOLUME AND DIRECTION OF FLUID FLOW THEREFROM, BEARING MEANSDISPOSED TO ROTATABLY SUPPORT SAID OPEN REARWARD END OF SAID DRUM, AMULTIRADIAL-CYLINDER HYDRAULIC MOTOR HAVING A ROTATING SHAFT SECURED TOTHE CLOSED FORWARD END OF THE DRUM, A BALL AND SOCKET JOINT DISPOSED TOSUPPORT SAID HYDRAULIC MOTOR